1. Field of the Invention
Various embodiments of the invention are directed to distributed process control systems. More particularly, various embodiments are directed to distributed systems requiring reduced bandwidth between at least data acquisition systems and remote equipment.
2. Background of the Invention
A growing trend in process control is distributed process control. Rather than having a single, centralized control center sending control commands to remote locations, the control functionality is moved closer to the controlled equipment. The centralized control center then may take a more supervisory role in the process control. For example, rather than sending a continuous stream of valve position commands to a valve controlling flow, the centralized control center may send a single flow set point to a remote process controller proximate to the valve, and allow the remote process controller to make valve position adjustments to achieve and maintain the desired flow.
Regardless of the location of the control functionality, the centralized control center may need a continuous or periodic stream of data from the remote locations for supervisory purposes. For example, if the remote operation is a hydrocarbon production well, the centralized control center may need to know the instantaneous flow rate of natural gas produced, the BTU content of the natural gas produced, and/or the instantaneous flow rate of oil produced. For these reasons, the centralized control center in distributed process control systems may be referred to as a supervisory control and data acquisition (SCADA) system.
SCADA systems may need data in as close to real time as possible. Thus, SCADA systems couple to the remote process controllers at the remote locations and continuously poll those controllers for data FIG. 1 illustrates a related art system in which a SCADA system 10 couples to a remote process controller 12 through a high bandwidth communication channel 14. The high bandwidth communication channel may take many forms, such as an Ethernet network, DSL or ADSL, single wire, radio based, satellite based communication, or a combination of one or more of these. Regardless of the physical structure of the high bandwidth communication channel, for proper operation the communication channel 14 should have sufficient bandwidth to support the continuous polling of the remote controller 12 by the SCADA system 10. Providing sufficient bandwidth, especially to remote locations, can be a recurring and major expense.
Thus, what is needed in the art is a mechanism to reduce the bandwidth requirements between SCADA systems and remote operations.